Aircraft typically comprise multiple compartments which are separated by walls or a floor. For example, the cockpit or flight deck is separated from the passenger compartment by a wall. In order to provide access between two adjacent compartments a door arrangement may be provided in the wall or floor separating the two compartments. Such door arrangement is typically configured for manual operation for opening and closing a door blade of the door arrangement.
It is desirable to be able to provide for automatic opening and closing of the door blade by an actuator, such as an electrically or pneumatically operable actuator. Such door actuators comprise a lever arm coupled between the actuator and the door blade. The lever arm mechanically couples the door blade to the actuator and translates movement of the actuator into a corresponding movement of the door blade. In this manner it is possible to selectively move the door blade between an open position and a closed position by operating the actuator.
However, it is important to take into consideration that sudden pressure drops may occur inside an aircraft and that in case of a pressure drop, i.e. decompression, in the compartment, into which the door blade moves upon opening, preventing structural damage to the aircraft requires the door blade to rapidly move from the closed position towards its open position. For example, a door arrangement between the cockpit and the passenger compartment is typically configured such that the door blade moves towards the cockpit upon opening, and in case of a pressure drop in the cockpit the door blade must rapidly move from the closed position towards the open position. Such movement may, however, be impeded by the mechanical link between the actuator and the door blade.